from PIL import Image
class ImageEditor():
	
    def __init__(self, filename):
        self.filename = filename
        self.original = None
        self.changed = list()

    def open(self):
        try:
            self.original = Image.open(self.filename)
        except:
           print('Файл не найден!')
        self.original.show()
    
    def do_bw(self):
        gray = self.original.convert("L")
        self.changed.append(gray)
        gray.save('gray.jpg')

MyImage = ImageEditor('original.jpg')
MyImage.open()
MyImage.do_bw()